A turbogenerator may comprise a turbine that is mechanically coupled to a generator. A rotor (e.g., turbine blade) associated with the turbine or the generator may have a rotational speed. Where the turbine is fed by exhaust gas of an internal combustion engine or steam associated therewith; a nozzle, injector, or electromechanical valve, solenoid, or the like may be controlled to manage the speed of the rotor. However, the nozzle, injector, electromechanical valve or solenoid may be subject to damage and reliability problems because of the thermal conditions associated with the exhaust stream or the byproducts of the combustion process. Accordingly, there is a need to control the rotational speed of the rotor of the turbogenerator that overcomes the aforementioned reliability problems.